Base station control method, base station control apparatus, wireless communication system and electronic device

ABSTRACT

A base station control method for a wireless communication system, a base station control apparatus, a wireless communication system and an electronic device. The wireless communication system includes a small cell. The base station control apparatus includes an upper limit determination unit and a frequency band control unit; wherein the upper limit determination unit is configured to determine the upper limit of the estimated number of small cells using unlicensed frequency bands in a target region according to available unlicensed frequency band resources and estimated service volume in the target region; and the frequency band control unit is configured to control one or more small cells to use or stop using the unlicensed frequency bands according to the upper limit of the estimated number, so that the number of small cells operating at the unlicensed frequency bands is not greater than the upper limit of the estimated number.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.15/304,783, filed Oct. 17, 2016, which is a National Stage applicationof International Application No. PCT/CN2015/079882, filed May 27, 2015,and claims priority to Chinese Application No. 201410227908.6, filed May27, 2014, the entire contents of which are incorporated herein byreference.

FIELD

The disclosure generally relates to the technical field of wirelesscommunications, and in particular to a base station controlling methodfor a wireless communication system, a base station controllingapparatus for a wireless communication system, and the wirelesscommunication system including the base station controlling apparatus.

BACKGROUND

With the continuous development of wireless communication industry,services for users to transmit data via a wireless network are increasedgradually, and the existing available spectrum resources of operatorsbecome increasingly difficult to meet users' demands for data. In orderto provide more wireless communications capacity for the users, a widelyaccepted solution is to use additional spectrum resources. Whilemaintaining the use existing frequency band, the users canopportunistically use the additional spectrum resources, such as atelevision frequency band, a 5 GHz frequency band, to support the user'sdata communications.

SUMMARY

In the existing solution of opportunistically using an unlicensed(unlicensed) frequency band, different communication systems ordifferent operators may simultaneously use a frequency band when usingan unlicensed spectrum, which may cause mutual interference.

A brief summary of the embodiments of the present disclosure areprovided below to provide some basic understanding to some aspects ofthe present disclosure. It should be understood that the summary is notexhaustive, and is not intended to identify a crucial or important partof the present disclosure or limit the scope of the present disclosure.The only purpose is to give some conception in a simplified manner as aprelude to the detailed description provided later.

In an aspect of the disclosure, a base station controlling method for awireless communication system is provided, wherein the wirelesscommunication system contains a small cell. The method includes a stepof determining an upper limit for the number of small cells using anunlicensed frequency band in a target area according to availableunlicensed frequency band resources and an estimated traffic in thetarget area. The method further includes a step of controlling one ormore small cells to stop operating in the unlicensed frequency band in acase that the number of the small cells operating in the unlicensedfrequency band is greater than the upper limit, so that the number ofthe small cells operating in the unlicensed frequency band is notgreater than the upper limit.

In another aspect of the disclosure, a base station controllingapparatus for a wireless communication system is provided, wherein thewireless communication system contains a small cell. The base stationcontrolling apparatus includes: an upper limit determination unit and anumber controlling unit. The upper limit determination unit isconfigured to determine an upper limit for the number of small cellsusing an unlicensed frequency band in a target area according toavailable unlicensed frequency band resources and an estimated trafficin the target area. The number controlling unit is configured to controlone or more small cells to stop operating in the unlicensed frequencyband in a case that the number of the small cells operating in theunlicensed frequency band is greater than the upper limit, so that thenumber of the small cells operating in the unlicensed frequency band isnot greater than the upper limit.

In yet another aspect of the disclosure, a wireless communication systemis provided, which includes a small cell and the base stationcontrolling apparatus according to an embodiment of the disclosure.

In still another aspect of the disclosure, a wireless communicationsystem is provided, which includes a control module and asynchronization module. The control module is configured to control theusage of an unlicensed frequency band of a first cell. The controlmodule includes a time slot determination unit configured to determine atime slot configuration for the first cell to use the unlicensedfrequency band resource, the time slot configuration including a judgingtime slot and a using time slot, so that the first cell does not use theunlicensed frequency band and determines whether another device is usingthe unlicensed frequency band in the judging time slot. In a case thatit is determined in the judging time slot that no other device is usingthe unlicensed frequency band, communication is performed using theunlicensed frequency band in the using time slot. The synchronizationmodule is configured to synchronize the time slot configurations of thefirst cell and a second cell in a case that it is determined that thefirst cell is interfered by the second cell using the unlicensedfrequency band, so that the judging time slots of the first cell and thesecond cell are synchronized.

In still another aspect of the disclosure, an electronic device isprovided, which includes a time slot configuration module, a judgingmodule and a signal transmission control module. The time slotconfiguration module receives time slot configuration information on theelectronic device from a control terminal and perform correspondingconfiguration. Wherein the time slot configuration includes a judgingtune slot and a using time slot. The judging module determines in thejudging time slot whether another device is using an unlicensedfrequency band based on the time slot configuration. Based on the timeslot configuration, the signal transmission control module does not usethe unlicensed frequency band to transmit a signal in the judging timeslot, and uses the unlicensed frequency band to transmit the signal inthe using time slot in a case that it is determined by the judgingmodule in the judging time slot that no other device is using theunlicensed frequency band. It is intermittently detected by the judgingmodule in the using time slot whether another device is using theunlicensed frequency band, and the detected other device is reported bythe judging module to the control terminal.

In still another aspect of the disclosure, an electronic device isprovided, which includes a carrier aggregation module and a controlmodule. The carrier aggregation module is configured to perform carrieraggregation communication with a first cell and a second cell via afirst carrier operating over an unlicensed frequency band and a secondcarrier operating over a licensed frequency band, respectively. Thecontrol module is configured to determine a time slot configurationincluding a judging time slot and a using time slot for the first cellto use the unlicensed frequency band, and control the electronic deviceto not monitor a signal of the first cell in the judging time slot andto acquire a control signaling from the second cell at least in thejudging time slot.

According to an embodiment, a base station controlling apparatus for awireless communication system is provided, wherein the wirelesscommunication system contains a small cell. The base station controllingapparatus includes: an upper limit determination unit and a frequencyband controlling unit. The upper limit determination unit is configuredto determine an estimated upper limit for the number of small cellsusing an unlicensed frequency band in a target area according toavailable unlicensed frequency band resources and an estimated trafficin the target area. The frequency band controlling unit is configured tocontrol one or more small cells to operate or stop operating in theunlicensed frequency band based on the estimated upper limit for thenumber, so that the number of the small cells operating in theunlicensed frequency band is controlled to be not greater than theestimated upper limit for the number.

According to another embodiment, a base station controlling method for awireless communication system is provided, wherein the wirelesscommunication system contains a small cell. The method includes a stepof determining an estimated upper limit for the number of small cellsusing an unlicensed frequency band in a target area according toavailable unlicensed frequency band resources and an estimated trafficin the target area. The method further includes a step of controllingone or more small cells to operate or stop operating in the unlicensedfrequency band based on the estimated upper limit for the number, sothat the number of the small cells operating in the unlicensed frequencyband is not greater than the estimated upper limit for the number.

The embodiments of the present disclosure are advantageous for ensuringthe communication quality in a case of opportunistically using anunlicensed frequency band.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure can be better understood by referring to thefollowing description taken in conjunction with the accompanyingdrawings. Same or similar reference characters indicate same or similarparts throughout the accompanying drawings. The accompanying drawingsare included in the description together with the followingspecifications as a part of the description for further illustratingpreferred embodiments with examples and explaining the principle andadvantages of the present disclosure. In the accompanying drawings:

FIG. 1 is a flow chart showing a process example of a base stationcontrolling method for a wireless communication system according to anembodiment of the disclosure;

FIG. 2 is a flow chart showing a sub process example of a base stationcontrolling method according to another embodiment;

FIG. 3 is a schematic diagram for illustrating a time slot settingexample specified by a base station controlling method according to anembodiment;

FIG. 4 is a flow chart showing a sub process example of a base stationcontrolling method according to yet another embodiment;

FIG. 5 is a block diagram showing a configuration example of a basestation controlling apparatus for a wireless communication systemaccording to an embodiment;

FIG. 6 is a block diagram showing a configuration example of a basestation controlling apparatus according to another embodiment;

FIG. 7 is a block diagram showing a configuration example of a basestation controlling apparatus according to yet another embodiment;

FIG. 8 is a block diagram showing a configuration example of a wirelesscommunication system according to an embodiment;

FIG. 9 is a schematic diagram for illustrating a wireless communicationsystem according to an embodiment of the disclosure;

FIG. 10 is a block diagram showing a configuration example of a wirelesscommunication system according to an embodiment;

FIG. 11 is a block diagram showing a configuration example of a wirelesscommunication system according to another embodiment;

FIG. 12 is a block diagram showing a configuration example of a wirelesscommunication system according to yet another embodiment;

FIG. 13 is a block diagram showing a configuration example of anelectronic device according to an embodiment;

FIG. 14 is a block diagram showing a configuration example of anelectronic device according to another embodiment;

FIG. 15 is a block diagram showing an exemplary structure of a computerfor implementing the method and apparatus according to the disclosure;and

FIG. 16 is a flow chart showing a process example according to anexemplary embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are described below with referenceto he companying drawings. Elements and features described in acompanying drawing or an embodiment may be combined with elements andfeatures illustrated in one or more other companying drawings orembodiments in the present disclosure. It should be noted thatpresentation and explanation of irrelevant components and processesknown by those skilled in the art are omitted in the companying drawingsand the description for clarity.

A base station controlling method according to an embodiment of thedisclosure may be applied to a wireless communication system containinga small cell. The small cell base station is a wireless access pointwith lower power, which includes, e.g., a femtocell base station, apicocell base station, a microcell base station and the like. The smallcell base station is deployed indoor or outdoor by the operator, inorder to improve the coverage of a macro base station and enhancenetwork capacity, etc. It should be noted that, although the small cellis taken as an example of a control object in the following exemplaryembodiments, the present disclosure is not limited to the control of thesmall-cell, and various specific areas using an unlicensed frequencyband in a wireless communication system may be controlled. For example,in a case that one or more of multiple sectors of the macro base stationuse unlicensed frequency spectrum resources, the switching of thesectors may be controlled according to the solution of the disclosure.Therefore, the term “small cell” herein should be broadly interpreted toinclude a variety of specific areas which can use an unlicensedfrequency band.

As shown in FIG. 1, a base station controlling method according to anembodiment of the disclosure may include a step of determining an upperlimit for the number of small cells using an unlicensed frequency bandin a target area according to available unlicensed frequency bandresources and an estimated traffic in the target area (S110), and a stepof controlling one or more small cells to stop operating in theunlicensed frequency band in a case that the number of the small cellsoperating in the unlicensed frequency band is greater than thedetermined upper limit, so that the number of the small cells operatingin the unlicensed frequency band is not greater than the upper limit(S120).

The target area is an area as a control target of the base stationcontrolling method, that is, the small cell base station in the area iscontrolled with the base station controlling method. The target area maycorrespond to: the coverage area of a macro base station, specific areas(such as a specified area, an area having a specific traffic level (in aspecific period of time)) in which a small cell is arranged in thecoverage area of a macro base station, an area of a specific coveragetype (such as overlapping with a coverage area of another macro basestation, or not overlapping with the coverage area of another macro basestation) or the like. The target area may be specified in advance, ormay also be dynamically adjusted according to actual operatingconditions (for example, traffic levels and coverage types).

With the base station controlling method according to the embodiment,the upper limit of the number of small cells opportunistically using anunlicensed frequency band is determined, the number of small cellsactually using the unlicensed frequency band is controlled to be notgreater than the upper limit, so that the communication quality in thetarget area reaches a predetermined level in probability. That is, themethod may not specifically determine which small cell or small cellsactually using the unlicensed frequency band, and which small cell orsmall cells are controlled to stop using the unlicensed frequency bandin a case that the number of small cells using the unlicensed frequencyband is greater than the determined upper limit of the number, but onlycontrol the total number of the small cells using the unlicensedfrequency band.

A variety of manners may be adopted to determine which small cell orsmall cells are controlled to use or stop using the unlicensed frequencyband. For example, a small cell with a high traffic (the number of usersor data traffic) may be preferentially controlled to use the unlicensedfrequency band, and a small cell with a low traffic may bepreferentially controlled to stop using the unlicensed frequency band.Alternatively, the small cell using or stopping using the unlicensedfrequency band may be determined according to the spatial distributionof the small cell, so that the spatial distribution of small cells usingthe unlicensed frequency band in the target area is uniform.Alternatively, the small cell using or stopping using the unlicensedfrequency band may be determined randomly.

In addition, the allocation of the unauthorized frequency band betweenthe small cells may be determined with the methods known in the art. Forexample, in an LTE (long term evolution) system, information isexchanged between small cells via an X2 interface to allocate theunlicensed frequency band resources. Alternatively, the allocation ofunlicensed frequency band resources may be determined at a macro basestation or a core network side.

A variety of ways may be used to determine the upper limit of the numberof small cells using the unlicensed frequency band. For example, thetotal number of small cells in the target area multiplied by a ratio maybe used as the upper limit of the number. Alternatively, a capacitydetermining method for common-frequency systems well known in the artmay be used to determine the upper limit of the number.

According to an embodiment of the disclosure, the upper limit for thenumber may be determined based on the estimation of communicationquality. Specifically, the upper limit may be determined such that, in acase that the number of small cells operating in the unlicensedfrequency band in the target area is not greater than the upper limit,the probability that a communication using the unlicensed frequency bandsatisfies a predetermined communication quality level reaches apredetermined threshold.

Specifically, a variety of interference indexes well known in the artmay be used, such as a signal to interference plus noise power ratio oran outage probability, and the probability that communication using theunlicensed frequency band satisfies a predetermined communicationquality level is estimated (for example, a proportion of users for whichthe communication satisfies the predetermined communication qualitylevel with respect to the users using the unlicensed frequency band),and thus the upper limit of the number of small cells using theunlicensed frequency band which corresponds to a predeterminedprobability threshold is determined.

Furthermore, in an embodiment of the disclosure, communications ofnon-guaranteed bit rate service is performed by the small cells usingthe unlicensed frequency band, and the user terminal transmits controlsignaling and performs data communications of which the quality ofservice needs to be guaranteed with the macro base station using alicensed frequency band, for example, which may be achieved throughcarrier aggregation. For example, reference is made to U.S. 20130195073A1, “Low-Cost LTE System with Distributed Carrier Aggregation on theUnlicensed Band”.

A licensed existing system which legally uses the unlicensed frequencyband (for the small cell) may exist in the coverage range of the smallcell, for example, a radar system of 5 GHz legally using the frequencyband of 5 GHz and a WiFi (wireless network) system of 2.4 GHz legallyusing the frequency band of 2.4 GHz. Therefore, in some embodiments ofthe disclosure, the protection of the existing system using theunlicensed frequency band is taken into account while the small cells iscontrolled to use the unlicensed frequency band, in order to achieve areasonable usage of the unlicensed frequency band between the existingsystem and the small cell.

As shown in FIG. 2, a base station controlling method according to anembodiment of the disclosure further includes a step S210 of specifyinga time slot configuration for the small cell using the unlicensedfrequency band. The time slot configuration may include a judging timeslot, an avoiding time slot and a using time slot.

In the judging time slot, the communication using the unlicensedfrequency band is stopped and it is determined whether another device(the existing system using the unlicensed frequency band, such as aradar, WiFi) is using the unlicensed frequency band. In a case that itis determined in the judging time slot that the other device is usingthe unlicensed frequency band, the following time slot is the avoidingtime slot. In the avoiding time slot, the communication using theunlicensed frequency band is suspended. In a case that it is determinedin the judging time slot that no other device is using the unlicensedfrequency band, the following time slot is the using time slot. In theusing time slot, the unlicensed frequency hand is used forcommunication. FIG. 3 shows a schematic diagram of an example of timeslot setting. For example, in the LTE system, the small cell basestation may send the set time slot information to a mobile terminal viaan SIB (system information block), and communications between the smallcell base station and the mobile terminal is performed according to theset time slot.

The durations of the judging time slot, the avoiding time slot and theusing time slot may be set in various ways. For example, the durationallocation of time slot may be set or adjusted dynamically according tothe utilization ratio of the unlicensed frequency band by the existingsystem using the unlicensed frequency band in a specific period of timeand/or area.

In addition, although it is determined in the judging time slot thatanother device is using the unlicensed frequency band so that thecommunication using the unlicensed frequency band is suspended in theavoiding time slot in the configuration example, the avoiding time slotmay also not be set separately. For example, a part or all of the usingtime slot may be set as that the unlicensed frequency band is not usedtherein for avoiding, or the judging time slot may be repeated onceagain.

Furthermore, the time slot setting may be adjusted dynamically accordingto the detection result for the existing system. In an embodiment, theduration of the avoiding time slot in the time slot setting is adjustedbased on the duration of another device using the unlicensed frequencyband which is detected in the avoiding time slot.

Specifically, in a case that it is determined in the judging time slotthat another device is using the unlicensed frequency band, the otherdevice using the unlicensed frequency band is monitored to determine theusage duration in the following avoiding time slot. For example, when itis determined that the usage duration is long, the duration of theavoiding time slot may be prolonged properly to reduce the interferencewith the other device; when it is determined that the usage duration isshort, the duration of the avoiding time slot may be reduced properly toimprove the efficiency of the present system using the unlicensedfrequency band.

In addition, according to an embodiment, in a process of communicationsin the using time slot, the small cell base station intermittentlydetects an unlicensed frequency band signal from other devices or othersmall cell base stations. As shown in FIG. 3, when communications isperformed in the using time slot, the small cell base station may usethe unlicensed frequency band in a way of alternating a communicationtime slot 301 and a detection time slot 303. For example, thecommunication using the unlicensed frequency band is performed in thecommunication time slot 301, and interference signals are detected inthe detection time slot 303. The interference signals may come fromother device using the unlicensed frequency band, such as a radar orWiFi, or may also come from other small cell base stations using theunlicensed frequency band. As will be described in more detail below,the interfering small cell may be a small cell of the present system, ormay also be a small cell in another system (of the same operator or adifferent operator). For example, it may be determined that whether thereceived interference signal comes from the same system or a differentsystem based on an ID of the detected cell or a cell manager ID. Theinformation may be used to modify overlapping coverage areas ofdifferent systems determined in advance based on the coverage area, ormodify potential interfering cell information. An example of determiningand modifying coverage types will be illustrated specifically withreference to FIG. 16 below.

When the unlicensed frequency band signal from another device isdetected in the using time slot, the communication in the using timeslot may be suspended, and the next using time slot is waited. In a casethat the interference signal is from another small cell of the system,the allocation of the unlicensed frequency band resources may beadjusted by exchanging information between the small cells, for example,via the X2 interface in the LTE, to avoid the interference betweenneighboring small cells. In a case that the interference signal is froma small cell of another system, the allocation of resources may beadjusted by exchanging information between different systems, to achievethe predetermined communication quality. For example, as describedbelow, no X2 interface is provided between small cells of differentsystems, and it is unable to directly exchange information to achievespectrum allocation. In this case, after the upper limit of the numberof the small cells in the overlapping coverage areas of differentsystems is determined, the upper limit of the number of the small cellsin each system is determined according to different demands of thesystems.

Next, a sub process of a base station controlling method according to anembodiment is illustrated with reference to FIG. 4. The embodiment isdirected to a case that the target area is an overlapping coverage area,that is, the coverage area of the system overlaps with that of anothersystem.

As shown in FIG. 4, the base station controlling method according to theembodiment further includes a step of determining a potentialinterfering small cell for the small cell of the present system (S410).In step S410, the potential interfering small cell is determinedaccording to coverage area information of a small cell in a neighboringsystem obtained from the neighboring system or detection on a signal ofa small cell of the neighboring system by the small cell of the presentsystem.

Here, the potential interfering small cell may be a small cell using theunlicensed frequency band, or may also be a small cell not using theunlicensed frequency band. The coverage area of the potentialinterfering small cell overlaps with that of the small cell of thepresent system or is close to the small cell of the present system.Therefore, interference on the small cell of the present system may becaused by the potential interfering small cell when it also using theunlicensed frequency band, hence it is referred to as the potentialinterfering small cell.

For example, in step S410, the coverage area information of the smallcell of the neighboring system may be obtained by exchanging informationwith the neighboring system, the small cell of the neighboring system isdetermined to be a potential interfering small cell for the small cellof the present system in a case that the coverage area of the small cellof the neighboring system overlaps with that of the small cell of thesystem or a distance between the small cell base station of theneighboring system and the small base station of the present system isless than a predetermined threshold. Alternatively, a potentialinterfering small cell may also be determined by the small cell basestation of the present system by detecting a signal of the small cellbase station of the neighboring system. For example, in a case that anintensity of the detected signal of the small cell base station of theneighboring system (the signal may be a signal in the licensed frequencyband or a signal in the unlicensed frequency band) is greater than apredetermined threshold, the small cell base station of the neighboringsystem is determined to be a potential interfering small cell. Asmentioned above, it may be determined whether the received interferencesignal is from the same system or a different system based on an ID ofthe detected cell or a cell manager ID.

In a case that the determined potential interfering small cell uses theunlicensed frequency band, the base station controlling method accordingto the embodiment of the disclosure may include a step of coordinatingwith the other system. As shown in FIG. 4, in an embodiment, in a casethat the potential interfering small cell uses the unlicensed frequencyband (it is determined to be Y in step S420), the method may furtherinclude a step of synchronizing a judging time slot of the small cell ofthe present system and a judging time slot of the small cell of theneighboring system (S440 and S445).

As mentioned above, the communication using the unlicensed frequencyband is stopped for the small cell and it is determined whether anotherdevice such as a radar or WiFi is using the unlicensed frequency band inthe judging time slot. The step of synchronizing a judging time slot ofthe small cell of the present system and a judging time slot of thesmall cell of the neighboring system is to avoid misidentifying anunlicensed frequency band signal of the small cell in the other systemas a signal of the other device such as a radar or WiFi.

Specifically, in a case that the present cell is a dominant cell (Y inS430), the neighboring system is notified to control the potentialinterfering small cell to have a judging time slot synchronized withthat of the small cell of the present system (S440). In a case that thepresent cell is not a dominant cell (N in S430), the judging time slotof the potential interfering small cell is acquired from the neighboringsystem, and the small cell of the present system is controlled to have ajudging time slot synchronized with that of the potential interferingsmall cell. Various ways may be used to determine the dominant cell. Forexample, the dominant cell is determined according to predeterminedappointment, or a small cell which first detects the potentialinterfering small cell is determined to be the dominant cell.

In addition, the step of coordinating with the other system may furtherinclude coordinating the unlicensed frequency band actually used. In anembodiment, in a case that the potential interfering small cell uses theunlicensed frequency band (it is determined to be Y in step S420), thebase station controlling method may further include a step ofcoordinating usages of unlicensed frequency band resources by the smallcell of the present system and the small cell of the neighboring system(S450, S455).

Specifically, in a case that the present cell is a dominant cell (V inS430), the neighboring system is notified of the unlicensed frequencyband actually used by the small cell of the present system (S450). In acase that the present cell is not a dominant cell (N in S430), theunlicensed frequency band actually used by the potential interferingsmall cell is acquired from the neighboring system and the small cell ofthe present system is controlled to not use the unlicensed frequencyband (S455).

The probability of communication quality reduction due to interferencecaused by the neighboring system using the same unlicensed frequencyband can be avoided by coordinating usages of the unlicensed frequencyband resources by the small cell of the present system and the smallcell of the neighboring system.

In a case that the target area is an overlapping coverage area, thesmall cell of the neighboring system in the target area may also betaken into account in the process of determining the upper limit for thenumber of small cells using the unlicensed frequency band in the targetarea. In an embodiment, in a case that a potential interfering smallcell exists in a target area, the upper limit for the number of smallcells of the present system and the number of potential interferingsmall cells using the unlicensed frequency band in the target area aredetermined according to traffics of the small cells of the presentsystem and the potential interfering small cell in the target area. Thatis, in a case that the target area is the overlapping coverage area andthe small cells of the present system using the unlicensed frequencyband may be interfered by the small cells of another system in theoverlapping coverage area, the upper limit for the total number of thesmall cells using the unlicensed frequency band is determined by takingthe small cells of the present system and the small cells of the othersystem in the target area into account, and the upper limits for thenumber of the small cells of the present system and the number of thesmall cells of the neighboring system using the unlicensed frequencyband in the target area are determined according to the upper limit forthe total number. According to the respective upper limits for thenumber, the small cells of the present system may be controlled, and,for example, the neighboring system may be notified by exchanginginformation between the systems, to control the small cells of theneighboring system, so that the total number of the small cells usingthe unlicensed frequency band in the target area is not greater than thedetermined upper limit for the total number.

In a specific embodiment, in a case that a potential interfering smallcell exists in a target area, the allocation of the number of smallcells of the present system and the number of potential interferingsmall cells of the other system using the unlicensed frequency band inthe target area is determined according to the ratio of the traffic ofthe small cells of the present system to the traffic of the potentialinterfering small cells of the other system in the target area. That is,on the basis that the upper limit for the total number of the smallcells of the present system and the small cells of the neighboringsystem using the unlicensed frequency band is determined, the allocationof the number of small cells of the present system and the number ofsmall cells of the neighboring system using the unlicensed frequencyband is further determined according to the traffics, and thus theunlicensed frequency band resources are allocated more reasonably. Inaddition, other ways for number allocation may also be used, forexample, the upper limits for the number of small cells of the presentsystem and the number of small cells of the neighboring system may bedetermined according to a ratio of the number of small cells of thepresent system to the number of small cells of the neighboring system inthe target area, or the number of small cells using the unlicensedfrequency band may be allocated equally.

In an example of the disclosure, time slot configuration information maybe notified by exchanging information between systems, to synchronizetime slot configurations of small cells. The exchange between systemsmay include mutually sending information between the present system andanother system, or may also include unilaterally sending information.More specifically, for example, different systems may have differentlevels. In a case that one of two systems is a dominant system (thuswhich time slot configuration to be used may be determined), only onesystem is required to provide the information. For example, a time slotconfiguration of a first cell is provided by the dominant system to adependent system, and the dependent system is controlled to be adjustedaccording to the time slot configuration. However, the disclosure is notlimited to the exemplary interacting manners.

Next, configuration examples of a base station controlling apparatus fora wireless communication system according an aspect of the disclosureare illustrated with reference to FIG. 5 to FIG. 7.

As shown in FIG. 5, a base station controlling apparatus 500 accordingto an embodiment of the disclosure includes an upper limit determinationunit 510 and a number controlling unit 520.

The upper limit determination unit 510 is configured to determine anupper limit for the number of small cells using an unlicensed frequencyband in a target area according to available unlicensed frequency bandresources and an estimated traffic in the target area.

According to an embodiment, the upper limit for the number is determinedby the upper limit determination unit according to the followingcriteria: in a case that the number of small cells operating in theunlicensed frequency band in the target area is not greater than theupper limit, the probability that a communication using the unlicensedfrequency band satisfies a predetermined communication quality levelreaches a predetermined threshold.

The number controlling unit 520 is configured to control one or moresmall cells to stop operating in the unlicensed frequency band in a casethat the number of the small cells operating in the unlicensed frequencyband is greater than the upper limit, so that the number of the smallcells operating in the unlicensed frequency band is not greater than theupper limit.

As shown in FIG. 6, a base station controlling apparatus 600 accordingto another embodiment of the disclosure includes an upper limitdetermination unit 610, a number controlling unit 620 and a time slotsetting unit 630. The upper limit determination unit 610 and the numbercontrolling unit 620 are similar to the upper limit determination unit510 and the number controlling unit 520. The time slot setting unit 630is configured to specify a time slot configuration for the small cellusing the unlicensed frequency band. The time slot configurationincludes a judging time slot, an avoiding time slot and a using timeslot. In the judging time slot, the communication using the unlicensedfrequency band is stopped and it is determined whether another devicesuch as a radar or WiFi is using the unlicensed frequency band. In acase that it is determined in the judging time slot that another deviceis using the unlicensed frequency band, the communication using theunlicensed frequency band is suspended in the avoiding time slot. In acase that it is determined in the judging time slot that no other deviceis using the unlicensed frequency band, the unlicensed frequency band isused for communication in the using time slot.

Although it is determined in the judging time slot that the other deviceis using the unlicensed frequency band and the communication using theunlicensed frequency band is suspended in the avoiding time slot in theconfiguration example, the avoiding time slot may also not be setseparately. For example, a part or all of the using time slot may be setas that the unlicensed frequency band is not used therein for avoiding,or the judging time slot may be repeated once again.

Furthermore, as shown in FIG. 6, the base station controlling apparatusaccording to an embodiment of the disclosure may further include a timeslot adjusting unit 640. The time slot adjusting unit 640 is configuredto adjust a duration of the avoiding time slot in the time slotconfiguration according to the duration of the other device using theunlicensed frequency band detected in the avoiding time slot. Forexample, when the duration of the other device using the unlicensedfrequency band is long, the duration of the avoiding time slot may beprolonged properly to reduce the interference with the other device;when the usage duration is short, the duration of the avoiding time slotmay be reduced properly to improve the efficiency of the present systemusing the unlicensed frequency band.

As shown in FIG. 7, a base station controlling apparatus 700 accordingto another embodiment of the disclosure includes an upper limitdetermination unit 710, a number controlling unit 720 and a potentialinterfering small cell determination unit 730. The upper limitdetermination unit 710 and the number controlling unit 720 are similarto the upper limit determination units and the number controlling unitsdescribed above. The potential interfering small cell determination unit730 is configured to determine a potential interfering small cell for asmall cell of the present system according to coverage area informationof a small cell in a neighboring system obtained from the neighboringsystem or detection on a signal of the small cell of the neighboringsystem by the small cell of the present system Although not shown inFIG. 7, the potential interfering small cell determination unit 730 mayinclude a unit configured to acquire the coverage area information ofthe small cell in the neighboring system or a unit configured to detectthe signal the small cell in the neighboring system.

In an embodiment, the upper limit determination unit 710 may beconfigured to determine the upper limits for the number of small cellsof the present system and the number of potential interfering smallcells using the unlicensed frequency band in the target area accordingto traffics of the small cells of the present system and the potentialinterfering small cells in the target area, in a case that it isdetermined by the potential interfering small cell determination unit730 that the potential interfering small cell exists in the target area.

For example, in a case that the target area is an overlapping area andthe small cells of the present system using the unlicensed frequencyband may be interfered by the small cell of the other system in theoverlapping area, the upper limit determination unit 710 determines theupper limit for the total number of the small cells using the unlicensedfrequency band by taking the small cells of the present system and thesmall cells of the other system in the target area together intoaccount, and determine the upper limits for the number of small cellbase stations of the present system and the number of small cell basestations of the neighboring system using the unlicensed frequency bandin the target area according to the upper limit for the total number.The number controlling unit 720 may control the small cell base stationsof the present system and, for example, notify the neighboring system tocontrol the small cell base stations of the neighboring system in thetarget area via a communication unit (not shown in FIG. 7), according tothe upper limits for the numbers, so that the total number of the smallcell base stations using the unlicensed frequency band in the targetarea is not greater than the determined upper limit for the totalnumber.

In a specific embodiment, the upper limit determination unit 710 may beconfigured to determine the allocation of the number of small cells ofthe present system and the number of potential interfering small cellsusing the unlicensed frequency band in the target area, according to aratio of the traffic (such as the number of users, or data traffic) ofthe small cells of the present system to the traffic of the potentialinterfering small cells.

Furthermore, as shown in FIG. 7, the base station controlling apparatusaccording to an embodiment of the disclosure may include a time slotsynchronization unit 740 configured to, in a case that the potentialinterfering small cell is using the unlicensed frequency band, notifythe neighboring system to control the potential interfering small cellto use a judging time slot synchronized with that of the small cell ofthe present system or making the small cell of the present system use ajudging time slot synchronized with that of the potential interferingsmall cell. As mentioned above, in the judging time slot, thecommunication using the unlicensed frequency band is stopped and it isdetermined whether another device is using the unlicensed frequencyband. Although not shown in FIG. 7, the time slot synchronization unit740 may include a unit configured to send time slot setting informationto the neighboring system or receive the time slot setting informationfrom the neighboring system.

In addition, as shown in FIG. 7, the base station controlling apparatusaccording to an embodiment of the disclosure may further include afrequency band coordination unit 750 configured to, in a case that thepotential interfering small cell is using the unlicensed frequency band,notify the neighboring system of the unlicensed frequency band actuallyused by the small cell of the present system, or acquire the unlicensedfrequency band actually used by the potential interfering small cellfrom the neighboring system and control the small cell of the presentsystem to not use the unlicensed frequency band. Although not shown inFIG. 7, the frequency band coordination unit 750 may include a unitconfigured to send frequency band using information to the neighboringsystem or receive the frequency band using information from theneighboring system.

FIG. 8 shows a block diagram of a configuration example of a wirelesscommunication system according to an embodiment of the disclosure. Thewireless communication system 800 includes a small cell base station 820and a base station controlling apparatus 810. The base stationcontrolling apparatus 810 may be configured as described in the aboveembodiments, which can determine an upper limit for the number of smallcells operating in the unlicensed frequency band in a target area withina coverage area of the wireless communication system 800, and controlthe small cell base station to stop operating in the unlicensedfrequency band in a case that the number of the small cells operating inthe unlicensed frequency band is greater than the determined upperlimit, so that the number of the small cells operating in the unlicensedfrequency band is not greater than the upper limit.

The base station controlling apparatus 810 may have variousconfigurations described with reference to FIG. 5 to FIG. 7.

The wireless communication system according to the embodiment of thedisclosure is further illustrated with reference to a schematic diagramin FIG. 9 below. FIG. 9 shows two wireless communication systems havingoverlapping coverage areas. A first system includes a macro base station910 and several small cell base stations 911, and a second systemincludes a macro base station 920 and several small cell base stations921. Furthermore, a mobile terminal 930 is also shown in FIG. 9. Forexample, the mobile terminal 930 may communicate a control signaling andguaranteed bit rate service with the macro base station, and may performnon-guaranteed bit rate communications such as data communications withthe small cell base station through the unlicensed frequency band. Asshown in FIG. 9, several devices using the unlicensed frequency band(such as a radar and WiFi) exist within the coverage range of the macrobase stations 910 and 920. Furthermore, FIG. 9 indicates an area 901covered by only the macro base station 910, an area 902 covered by onlythe macro base station 920 and an overlapping coverage area 903 coveredby the macro base station 910 and the macro base station 920.

For a target area within the non-overlapping coverage area 901 or 902,the base station controlling apparatus (not shown in FIG. 9, which maybe arranged in the macro base station, the small cell base station or atthe core network side) determines the upper limit for the number ofsmall cells using the unlicensed frequency band and controls the smallcells according to the upper limit for the number. For a target areawithin the overlapping coverage area 903, the base station controllingapparatus determines the upper limits for the number of small cells ofthe present system and the number of potential interfering small cellsusing the unlicensed frequency band in the target area, for example, byexchanging information between the macro base station (for example 910)of the present system and the macro base station (for example 920) ofthe neighboring system or according to the detection on a signal of thesmall cell base station 921 of the neighboring system by the small cellbase station 911 of the present system, and controls the small cell basestations of the present system and notifies the neighboring system tocontrol the small cell base station thereof by exchanging informationbetween the macro base stations, so that the number of small cells usingthe unlicensed frequency band in the target area is not greater than theupper limit for the number.

As shown in FIG. 10, in an embodiment of the disclosure, a wirelesscommunication system 1000 is provided, which includes a control module1010 and a synchronization module 1020.

It should be noted that, components of the system may be arranged on adevice (for example a chip), or may also be separately arranged onmultiple devices. For example, the control module may be arranged inoperation, management and maintenance devices (OAM) or a mobilemanagement entity (MME), and the synchronization module may be arrangedin the small cell base station. In an example, the whole system isarranged in the OAM, MME or the macro base station. In another exampleof the disclosure, different systems are managed by different networkoperators.

The control module 1010 is configured to control the usage of anunlicensed frequency band by a first cell.

The control module 1010 includes a time slot determination unit 1012configured to determine a time slot configuration for the first cell touse the unlicensed frequency band resource. The time slot configurationmay include a judging time slot and a using time slot. The controlmodule 1010 may be configured to control the first cell to not use theunlicensed frequency band and determine whether another device is usingthe unlicensed frequency band in the judging time slot. In a case thatit is determined in the judging time slot that no other device is usingthe unlicensed frequency band, communication is performed using theunlicensed frequency band in the using time slot.

The synchronization module 1020 is configured to synchronize the timeslot configurations of the first cell and a second cell, in a case thatit is determined that the first cell is interfered by the second cellusing the unlicensed frequency band, so that the judging time slots ofthe first cell and the second cell are synchronized.

In addition, the time slot configuration determined by the time slotdetermination unit 1012 may further include an avoiding time slot, andthe control module 1010 may be configured to suspend the communicationusing the unlicensed frequency band in a case that it is determined inthe judging time slot that another device is using the unlicensedfrequency band. However, the avoiding time slot may also not be setseparately. For example, a part or all of the using time slot may be setas that the unlicensed frequency band is not used therein for avoiding,or the judging time slot may be repeated once again. In an example, theother device is a authorized device having a legal right to use theunlicensed frequency band, to protect the authorized device to operatenormally in the respective frequency band.

In addition, in a case that the second cell is managed by anothersystem, the wireless communication system may further include aninteraction interface for interaction between the systems in anembodiment.

As shown in FIG. 11, similar to the above wireless communication system1000, a wireless communication system 1100 include a control module 1110and a synchronization module 1120. Furthermore, the system 1100 mayinclude an interaction interface 1130.

The interaction interface 1130 is configured to exchange, with the othersystem, information on the first cell or the second cell including thetime slot configuration of the first cell or the second cell, in orderthat the synchronizing module 1120 synchronizes the time slotconfigurations of the first cell and the second cell.

It should be noted that, the “exchange, with the other system,information on the first cell or the second cell” as described hereinmay include mutually sending information between the present system andthe other system, or may also include unilaterally sending information.More specifically, in a case that one of two systems is a dominantsystem (thus which time slot configuration to be used may bedetermined), only one system is required to provide information. Forexample, a time slot configuration of the first cell is provided by thedominant system to a dependent system, and the dependent system isrequired to be adjusted according to the time slot configuration.However, the disclosure is not limited to these specific exemplaryinteracting manners.

As shown in FIG. 11, in an embodiment, the wireless communication systemmay further include a coordination module 1140, The coordination module1140 may be configured to coordinate usages of the unlicensed frequencyband by the first cell and the second cell to reduce interference. Theinformation on the first cell or the second cell exchanged byinteraction interface 1130 with the other system may further include theunlicensed frequency band actually used by the first cell or the secondcell, for the coordination performed by the coordination unit.

In addition, in another embodiment, the interaction interface may beconfigured to exchange, with the other system, information on the firstcell or the second cell including a coverage area, in order that thesynchronization module determines interference on the first cell by thesecond cell using the unlicensed frequency band based on the coveragearea.

In a case that the first cell is at least partially arranged in thecoverage range of a third cell managed by the present system, thewireless communication system may further include a user managementmodule in an embodiment.

As shown in FIG. 12, similar to the above wireless communication system1000, a wireless communication system 1200 include a control module 1210and a synchronization module 1220. Furthermore, the system 1200 alsoincludes a user management module 1230.

The user equipment management module 1230 is configured to determine auser equipment located in the first cell and served by the third cell,instruct the user equipment to add the first cell to perform carrieraggregation with the third cell, and notify the user equipment of thetime slot configuration of the first cell.

For example, the user equipment management module 1230 may instruct theuser equipment to add the first cell to perform carrier aggregation witha macro cell, and notify the user equipment of the time slotconfiguration of the first cell, through a downlink shared channel(DL-SCH).

In practice, the adding of the cell and the notifying of the time slotconfiguration may be implemented via one signaling, or may also beimplemented via two signaling, For example, wireless resource control(RRC) signaling (for example a RRCConnectionReconfiguration signaling)may be issued by the macro cell to send the two kinds of information.The RRC signaling of the macro cell may also be used to instruct theadding of the cell, and the SIB information of the first cell is used tonotify the time slot configuration (for example, when the time slotconfiguration changes after a small cell is added). The RRC signalingand the SIB information are carried by the DL-SCH channel.

In a specific embodiment, in a case that the first cell is a small cellusing the unlicensed frequency band and the third cell is a small cellusing the licensed frequency band, the user equipment management modulemay control the user equipment to receive a control signal from thethird cell and receive a data signal from the first cell, and thusobtain the important control information over a stable link. In anexample, the third cell is configured to be a primary cell for the userequipment, the first cell is configured to be a secondary cell for theuser equipment, and communication resources of the first cell and theuser equipment are scheduled by the third cell.

Furthermore, in a specific embodiment, the controlling module maycontrol the usage of unlicensed frequency band resources of multiplecells containing the first cell, and the time slot determination modulemay determine multiple time slot configurations based on the locationsof multiple cells.

For example, the time slot determination module may determine multipletime slot configurations according to the types of the area where itlocates, to improve the usage efficiency of the unlicensed frequencyband. For example, two small cells, which are sufficiently distant apartfrom each other such that no mutual interference is caused, may havedifferent time slot configurations. As another example, a shorter usagetime slot may be set in a case where more authorized users (such asWiFi) are around a small cell A; a longer usage time slot may be set ina case where less authorized users are around a small cell B.

FIG. 13 shows an electronic device according to an embodiment of thedisclosure. The electronic device 1300 includes a time slotconfiguration module 1310, a judging module 1320 and a signaltransmission control module 1330.

The time slot configuration module 1310 receives time slot configurationinformation on the electronic device from a control terminal and performcorresponding configuration, wherein the time slot configurationincludes a judging time slot and a using time slot.

The judging module 1320 determines in the judging time slot whetheranother device is using an unlicensed frequency band, based on the timeslot configuration.

The signal transmission control module 1330 do not use the unlicensedfrequency band to transmit a signal in the judging time slot, based onthe time slot configuration. The signal transmission control module 1330performs a control to use the unlicensed frequency band to transmit asignal in the using time slot in a case that it is determined by thejudging module 1320 in the judging time slot that no other device isusing the unlicensed frequency band.

The judging module 1320 intermittently detects whether another device isusing the unlicensed frequency band, and reports the detected otherdevice to the control terminal in the using time slot.

For example, the judging module 1320 may access a specialized databasefor managing the unlicensed spectrum resources to determine whetheranother device is using the unlicensed frequency band in the judgingtime slot, and the time slot configuration module 1310 may adjust anavoiding time slot based on the information obtained by the judgingmodule 1320 by accessing the database.

In an embodiment, the time slot configuration may further include anavoiding time slot. The signal transmission control module 1330 performsa control to suspend the communication using the unlicensed frequencyband in the avoiding time slot, in a case that it is determined by thejudging module 1320 in the judging time slot that another device isusing the unlicensed frequency band. However, the avoiding time slot mayalso not be set separately. For example, a part or all of the using timeslot may be set as that the unlicensed frequency band is not usedtherein for avoiding, or the judging time slot may be repeated onceagain.

In an embodiment, the electronic device 1300 may embed the time slotconfiguration information into an SIB and send the SIB to a userequipment served by the electronic device.

Based on the time slot configuration information, the user equipment maybe in an inactive state in the judging time slot, so no power isconsumed to monitor resource scheduling information for the small cell,and monitors only in the using time slot. For example, correlationparameters for discontinuous reception (DRX) may be set according to thetime slot configuration.

The electronic device 1300 according to the embodiment may be, forexample, arranged in a small cell base station.

FIG. 14 shows an electronic device according to another embodiment. Theelectronic device 1400 includes a carrier aggregation module 1410 and acontrol module 1420.

The carrier aggregation module 1410 is configured to perform carrieraggregation communication with a first cell and a second cell via afirst carrier operating over an unlicensed frequency band and a secondcarrier operating over a licensed frequency band, respectively.

The control module 1420 is configured to determine a time slotconfiguration including a judging time slot and a using time slot forthe first cell to use the unlicensed frequency band resource, andcontrol the electronic device 1400 to not monitor a signal of the firstcell in the judging time slot and to acquire a control signaling fromthe second cell at least in the judging time slot. The control signalingincludes, for example, a judging result, the setting or adjusting of theavoiding time slot, scheduling information on communication resourcesfor carrying traffic data to be used by the first cell in the using timeslot, etc.

The electronic device 1400 may receive the SIB information from thefirst carrier and acquire a time slot configuration from the SIBinformation. Alternatively, the electronic device 1400 may receive anRRC signaling from the second carrier and acquire a time slotconfiguration from the RRC signaling.

In addition, the electronic device 1400 may determine DRY parametersaccording to the time slot configuration.

In an example, various steps of the above methods and various componentsand/or units of the above apparatus may be implemented in software,firmware, hardware or a combination thereof. In a case of implementingin software or firmware, a program of a software for implementing theabove methods may be installed from a storage medium or a network to acomputer (such as the general-purpose computer 1500 shown in FIG. 15)having dedicated hardware. The computer can perform various functions ifinstalled with various programs.

In FIG. 15, a computation processing unit (i.e., CPU) 1501 executesvarious processing according to a program stored in a Read Only Memory(ROM) 1502 or a program loaded to a Random Access Memory (RAM) 1503 froma storage section 1508. In the RAM 1503, if necessary, data required forthe CPU 1501 in executing various processing and the like is alsostored. The CPU 1501, the RUM 1502 and the RAM 1503 are linked to eachother via a bus 1504, An input/output interface 1505 is also linked tothe bus 1504.

The following components are linked to the input/output interface 1505:an input section 1506 including a keyboard, a mouse and the like, anoutput section 1507 including a display such as a Cathode Ray Tube (CRT)and a Liquid Crystal Display (LCD), a speaker and the like, the storagesection 1508 such as a hard disk and the like, and a communicationsection 1509 such as a network interface card like a LAN card, a modemand the like. The communication section 1509 performs communicationprocessing via a network such as the Internet. If necessary, a drive1510 can also be linked to the input/output interface 1505. A removablemedium 1511 such as a magnetic disk, an optical disk, a magneto-opticaldisk, a semiconductor memory and the like is mounted on the drive 1510as required such that a computer program read out therefrom is installedin the storage section 1508 as required.

In a case that the series of processing above is implemented insoftware, a program constituting the software is installed from thenetwork such as the Internet or the storage medium such as the removablemedium 1511.

It is understood by those skilled in the art that the storage medium isnot limited to the removable medium 1511 shown in FIG. 15 in which theprogram is stored and which is distributed separately from the device soas to provide the program to the user. Examples of the removable medium1511 include a magnetic disk including a Floppy Disk (registeredtrademark), an optical disk including a Compact Disk Read Only Memory(CD-ROM) and a Digital Versatile Disc (DVD), a magneto-optical diskincluding a MiniDisc (MD) (registered trademark), and a semiconductormemory. Alternatively, the storage medium may be the ROM 1502, the harddisk contained in the storage section 1508 or the like. Herein, theprogram is stored in the storage medium, and the storage medium isdistributed to the user together with the device containing the storagemedium.

Embodiments of the present disclosure also relates to a program producton which machine-readable instruction codes are stored. The instructioncodes can perform the methods according to the above embodiment whenread and executed by a machine.

Accordingly, the present disclosure also includes storage mediumcarrying the program product on which the machine-readable instructioncodes are stored. The storage media includes a soft-disk, an opticaldisk, a magnetic disk, a storage card, a storage stick and the like, butis not limited thereto.

Embodiments of the present disclosure further include an electronicdevice as follows. The electronic device may be a base station/a userequipment, or a chip therein. The user equipment may be a mobileterminal with a communication function, such as a mobile phone, acomputer, a smart watch, smart glasses, and a vehicle.

According to an embodiment, an electronic device for a wirelesscommunication system is provided, wherein the wireless communicationsystem contains a small cell. The electronic device includes a circuitryconfigured to determine an upper limit for the number of small cellsusing an unlicensed frequency band in a target area according toavailable unlicensed frequency band resources and an estimated trafficin the target area; and control one or more small cells to stopoperating in the unlicensed frequency band in a case that the number ofthe small cells operating in the unlicensed frequency band is greaterthan the upper limit, so that the number is not greater than the upperlimit.

According to an embodiment, a wireless communication system is provided,which includes a control module and a synchronization module. Thecontrol module is configured to control the usage of an unlicensedfrequency band by a first cell. The control module includes a circuitryconfigured to determine a time slot configuration including a judgingtime slot and a using time slot for the first cell to use the unlicensedfrequency band resource, so that the first cell does not use theunlicensed frequency band and determines whether another device is usingthe unlicensed frequency band in the judging time slot. In a case thatit is determined in the judging time slot that no other device is usingthe unlicensed frequency band, communication is performed using theunlicensed frequency band in the using time slot. The synchronizationmodule includes a circuitry configured to synchronize the time slotconfigurations of the first cell and a second cell in a case that it isdetermined that the first cell is interfered by the second cell usingthe unlicensed frequency band, so that the judging time slots of thefirst cell and the second cell are synchronized.

In another aspect of the disclosure, an electronic device is provided,which includes a circuitry configured to receive time slot configurationinformation on the electronic device from a control terminal and performcorresponding configuration, the time slot configuration including ajudging time slot and a using time slot; determine in the judging timeslot whether another device is using an unlicensed frequency band basedon the time slot configuration; based on the time slot configuration, donot use the unlicensed frequency band to transmit a signal in thejudging time slot, and use the unlicensed frequency band to transmit thesignal in the using time slot in a case that it is determined by thejudging module in the judging time slot that no other device is usingthe unlicensed frequency band; and intermittently detect in the usingtime slot whether another device is using the unlicensed frequency band,and report the detected other device to the control terminal.

In still another aspect of the disclosure, an electronic device isprovided, which includes a circuitry configured to: perform carrieraggregation communication with a first cell and a second cell via afirst carrier operating over an unlicensed frequency band and a secondcarrier operating over a licensed frequency band, respectively;determine a time slot configuration including a judging time slot and ausing time slot for the first cell to use the unlicensed frequency bandresource, and control the electronic device to not monitor a signal ofthe first cell in the judging time slot and to acquire a controlsignaling from the second cell at least in the judging time slot.

As mentioned above, the small cell generating interference may belong tothe same system as the current small cell, or may also be a small cellof another system of the same operator or a different operator.Accordingly, different types of coverage areas may be defined. Forexample, under the coexistence of multiple systems, the coverage rangeof the secondary cell within the coverage range of the primary cell maybe grouped into two types: a first type, i.e., an overlapping area whichexists in the coverage ranges of the primary cells belonging todifferent operators and the unlicensed frequency band may be used in thecoverage ranges of the primary cells; and a second type, i.e., an areain the coverage range of only one operator here the unlicensed frequencyband may be used.

Next, an exemplary embodiment is illustrated with reference to FIG. 16.

In step S1610, a management area is determined. The management area maybe an area of a specific type determined for facilitating management,and spectrum management may be performed for the area in a uniformmanner.

Specifically, the type of the area and the management area may bedetermined by exchanging information on the service area between theoperators, such as a coverage range and an area where the unlicensedfrequency band may be used.

Next, for the determined management area, time slot setting (S1620),spectrum resource allocation (S1630) and automatically adjustment of theusage of the unlicensed frequency band with the allocated resources(S1640) may be performed in the manner as previously described.

In step S1650, interference feature of the neighboring cell is detectedby the secondary cell using the unlicensed frequency band, and theresult is sent to a spectrum management device.

Communication systems of different operators may be determined based onthe measurement of interference from different systems by the secondarycell and/or the user when the secondary cell uses the unlicensedfrequency band to provide the user with additional bandwidths. Forexample, users of two operators always may detect interference from theneighboring cells at some locations and these cells belong to differentoperators. For example, the secondary cell may intermittently detect thefrequency band (for example, in a intermittent transmission and networklistening mode in the LTE system) in the time slot of the secondary cellusing the unlicensed frequency band. Through frequency band listening,the secondary cell may detect information from a neighboring secondarycell, such as, an ID of a cell or a spectrum manager ID of the cell. TheID of secondary cell or the manager ID may be determined by a spectrummanagement device of the system. When an overlapping area exists inprimary base stations of different operators, the primary systemexchanges information on the ID of the cell or ID of the manager of thecell, and sends the information to the secondary cell. The informationmay also be sent to a user terminal through the unlicensed frequencyband. The base station or the terminal, when detecting the interferenceof the neighboring cell, may determine whether the interference comesfrom a cell of the same operator or a cell of a different operatoraccording to the known ID of the cell or the ID of the manager of thecell. If interference of a secondary cell within a primary cell fromdifferent operators is detected by the secondary cell or the userterminal in the unlicensed frequency band at a location, it shows thatthe location is in the above-described area of first type. The secondarycell may send the information to the spectrum management device of theprimary cell, for example, through a backbone. The user terminal maysend the information to the spectrum management device via the primarycell of the authorized network.

With the information, the spectrum management device may create ormodify the range of the area of the first type. Interference within thearea of the second type comes from the same operator, and may beeliminated according to the spectrum usage strategy of the operator.After the available spectrum resources in the area are determined, eachneighboring cell can automatically select and use a frequency band toavoid interference. For interference among cells from differentoperators in the area of the first type, interference of neighboringcells may be coordinated by exchanging information between operators.

Based on the information obtained by way of the above example, when itis determined that the management area need to be modified (“Yes” inS1660), the management area is modified (S1670). For example, the mannerof spectrum management is adjusted correspondingly based on the changeof the area of first type or the area of second type. When themanagement area need not to be modified (“No” in S1660), the unlicensedfrequency band is used continually according to the spectrum using timeslot (S1680).

In the above description of embodiments of the present disclosure, afeature described and/or illustrated in an embodiment may be applied toone or more other embodiments in a same or similar manner, or may becombined with a feature in other embodiments, or may replace a featurein other embodiments.

It should be emphasized that, the term “include/contain”, as used in thepresent disclosure, means existence of a feature, an element, a step ora component, but does not exclude existence or addition of one or moreother features, elements, steps or components.

In the above examples and embodiments, numeric reference characters areused for representing various steps and/or units. Those skilled in theart should understand that the reference characters are only used forfacilitating description and illustration rather than representing anorder or other limits.

Furthermore, the methods in the present disclosure are not limited to beperformed in the time order as described, but may be performed in othertime orders or in parallel or independently. Therefore, the performingorder of the method described in the present disclosure is not a limitto the technical scope of the present disclosure.

Although the invention is disclosed by describing the above embodimentof the present disclosure, it should be noted that each of the aboveexample and embodiment is not for limiting but for illustrating. Thoseskilled in the art may make various modifications, improvements andequivalents within the spirit and scope of the appended claims. Themodifications, improvements and equivalents should also be included inthe protection scope of the present disclosure.

1. A wireless communication system, comprising: a control module configured to control the usage of an unlicensed frequency band by a first cell, wherein the control mode le comprises a time slot determination unit configured to determine a time slot configuration comprising a judging time slot and a using time slot for the first cell to use the unlicensed frequency band resource, such that the first cell does not use the unlicensed frequency band and determine whether another device is using the unlicensed frequency band in the judging time slot, and communication is performed using the unlicensed frequency band in the using time slot in a case that it is determined in the judging time slot that no other device is using the unlicensed frequency band; and a synchronization module configured to synchronize the time slot configurations of the first cell and a second cell in a case that it is determined that the first cell is interfered by the second cell using the unlicensed frequency band, so that the judging time slots of the first cell and the second cell are synchronized.
 2. The wireless communication system according to claim 1, wherein the time slot configuration determined by the time slot determination unit further comprises an avoiding time slot, the usage of the unlicensed frequency band is suspended in the avoiding time slot in a case that it is determined in the judging time slot that another device is using the unlicensed frequency band.
 3. The wireless communication system according to claim 1, wherein the second cell is managed by another system, and the system further comprises: an interaction interface configured to exchange, with the other system, information on the first/second cell comprising the time slot configuration of the first/second cell, for the synchronizing module to synchronize the time slot configurations of the first cell and the second cell.
 4. The wireless communication system according to claim 3, further comprising a coordination module configured to coordinate usages of the unlicensed frequency band by the first cell and the second cell to reduce interference, wherein the information on the first/second cell exchanged via the interaction interface with the other system further comprises the unlicensed frequency band actually used by the first/second cell, for coordination performed by the coordination unit.
 5. The wireless communication system according to claim 1, wherein the second cell is managed by another system, and the system further comprises: an interaction interface configured to exchange, with the other system, information on the first/second cell comprising a coverage area, for the synchronization module to determine interference on the first cell by the second cell using the unlicensed frequency band based on the coverage area.
 6. The wireless communication system according to claim 1, wherein the first cell is at least partially located in a coverage range of a third cell managed by the system, and the system further comprises: a user equipment management module configured to determine a user equipment located in the first cell and served by the third cell, instruct the user equipment to add the first cell to perform carrier aggregation with the third cell, and notify the user equipment of the time slot configuration of the first cell.
 7. The wireless communication system according to claim 6, wherein the user equipment management module instructs the user equipment, through a DL-SCH channel, to add the first cell to perform a carrier aggregation with a macro cell, and notifies the user equipment of the time slot configuration of the first cell.
 8. The wireless communication system according to claim 6, wherein the first cell is a small cell, the third cell uses a licensed frequency band, the user equipment management module controls the user equipment to receive a control signal from the third cell and receive a data signal from the first cell.
 9. The wireless communication system according to claim 1, wherein the control module controls the usage of unlicensed frequency band of a plurality of cells comprising the first cell, and the time slot determination module determines multiple time slot configurations based on locations of the plurality of cells. 